Both the British and Irish Governments confirmed early on that there were no plans to introduce controls on the 224-mile long border between the Republic and the North. Over the past month it has become clear that the Home Office intends to deal with this gaping hole in the scheme by introducing e-borders checks between Northern Ireland and Britain.

This outcome, and the rationale behind it, was predicted by The Register back in October:

Although e-borders is primarily aimed at policing international borders, it is heavily dependent on advanced passenger information that is gathered by airlines and ferry companies on behalf of the UK Government. This information can and will also be used for security on internal flights and ferry journeys, including those between Northern Ireland and the mainland. But being required to produce a passport or ID card as proof of identity prior to boarding a plane does not necessarily mean you're passing passport control at an international border. Got that?

Exactly this sleight of hand was employed by Gordon Brown in early January, when he wrote to Northern Ireland's First Minister, Ian Paisley, assuring him that "there is no question of instituting passport control for people travelling within the United Kingdom."

Accepting this statement at face value, Dr Paisley stated that: "It is only right and proper that British citizens in Northern Ireland are treated on a par with their fellow-countrymen in the rest of the UK."

Less than a week later, however, Conservative Northern Ireland spokesman Owen Paterson secured a revealing parliamentary answer from Home Office Minister Liam Byrne, on new police powers to capture passenger information on air and sea journeys within the UK.

It is expected that this police power will only apply to air and sea routes between Great Britain and Northern Ireland. Passengers will not be required to use passports, but may be required to produce one of several types of documentation, including passports, when travelling, to enable the carrier to the meet the requirements of a police request

If these proposals go forward people in Northern Ireland, who are citizens of the United Kingdom, will have restrictions placed on their travel to Great Britain yet, shockingly, this scheme will not be applied to those coming into Great Britain from the Republic of Ireland or France. If this plan goes ahead, the people of Northern Ireland will be treated worse than foreigners

In one respect at least, Wilson was exaggerating. Equivalent controls will be introduced between Britain and the Republic, according to a Freedom of Information response issued at the same time as Gordon Brown's letter to Dr Paisley.

"In the case of British and Irish passengers travelling between the Republic of Ireland and Great Britain by air and sea, passenger information will be required to conduct customs and policing checks but not immigration checks," e-borders programme director Julie Gillis said.

Although it is not currently mandatory to carry passports/national ID cards for travel within the CTA (Common Travel Area), for their own purposes the air and sea carriers require evidence of identity, which is normally photographic ID. It is not yet clear how passport data will be collected by HMG on CTA routes. It is possible that passports will need to be carried by CTA nationals in future to provide information to e-borders. Analysis suggests that passports are already carried by most passengers as tokens of identity on CTA routes. Differing levels of scrutiny are necessary for passengers travelling to and within the UK

Gillis' response also states that these security checks will be maintained irrespective of any possible arrangements that might be reached between the British and Irish Governments. There seems little prospect therefore of bringing the Republic within the e-border zone, as suggested by Lord Trimble.

Short of scrapping the scheme entirely, there is no obvious way of reconciling e-borders with unionist sensibilities. And by trying to impose a cordon sanitaire around the UK, the British Government has effectively opened up a new faultline in the union. As things stand, travellers from Belfast will soon find that they require identification to travel to London, but not to Dublin. The symbolism of the situation will be missed by nobody in Northern Ireland.